Can't get past 16 Bit

[billt]

Using optical input, for some reason trying to play known files that are 24bit / 192 kHz only play playing back at 16 bit on app file info.
Test file in Wiim plays back correctly at 24/192 preset. Using Modi 3+ DAC and always played back accordingly when using Volumio.
Swapped out optical cables, same result. Thanks in advance for any help.

 

[Mr Ee]

Wondering if the wiim optical input always does digital to analog conversion, and is undergoing adc on the way back out the optical out, i.e. not passing through the optical signal?